Figure 1a:

Sequence diagrams illustrate (a) dark-artery MR angiography procedure, with FSD-prepared balanced SSFP (bSSFP) triggered at systole and (b) bright-artery MR angiography procedure, with T2-prepared (T2_prep) balanced SSFP triggered at diastole. Both FSD preparation and T2 preparation consist of 90°x-180°y-90°x radiofrequency (RF) series and are of the same duration to maintain the same T2 weighting for venous blood and static tissues. FSD gradient pulse applied in readout direction (G_RO) and FSD gradient pulse applied in phase-encoding direction (G_PE) are simultaneously switched on in FSD preparation but switched off in T2 preparation. Readout direction coincides with main blood flow direction. FSD or T2 preparation is followed by a spectrally selective fat-saturation (Fat Sat) radiofrequency module and 10 preparation radiofrequency pulses with linearly increasing flip angles before the balanced SSFP data acquisition. R = R wave, s = sample.